One recent weapon is what frog-busters are calling a "hot shower chamber, " a modified freight container used by nurseries to ship plants, with multiple heads that spray heated water onto the plants and kill any coquis that might be lurking there.

WSJ: When It Gets Too Noisy in Paradise, They Call the Frog Whisperer

When the sides were heated, the electrons in the atoms become agitated and emit radiation, which bounces around the container, being continuously absorbed and re-emitted.

WSJ: Book Review: Surfaces and Essences

Phthalates, the chemicals that make a PVC container flexible, "can migrate out of the plastic when it's heated, " says Dr. Halden, who has done comprehensive studies on emerging contaminants and plastics for more than a decade.

WSJ: Is It Safe to Heat Food in Plastic?